JP3838765B2 - Tonometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention is for measuring intraocular pressure.EyesRegarding pressure gauge.
[0002]
[Background]
Conventionally, intraocular pressure measurement using a tonometer has been performed in order to detect glaucoma and examine its therapeutic effect. Since there are individual differences in intraocular pressure, it is necessary to examine periodic fluctuations such as diurnal fluctuations by periodically measuring when examining the treatment effect and progress of glaucoma. For this reason, a tonometer that can easily measure intraocular pressure at home or the like is eagerly desired.
[0003]
As the tonometer, a contact applanation tonometer that directly applanates the cornea and a non-contact tonometer that applanates with air are mainly known.
For example, a Goldmann applanation tonometer is known as a highly accurate contact applanation tonometer. This Gordmann applanation tonometer is an apparatus that obtains intraocular pressure from the pressing force required to reach a predetermined applanation area after applying eye anesthesia and then pressing the pressing member directly against the cornea of the eye to be examined. is there.
[0004]
Further, as a contact applanation tonometer excellent in portability, there is one using the measurement principle of a McKay-Marg tonometer (Japanese Patent Publication No. 8-000107). In this tonometer, the cornea is applanated with a flat contact head with a base around the central post, the force applied to the central post is measured, and the intraocular pressure is obtained from the drop point in the waveform of this force. ing.
That is, as the spherical cornea is applanated, the force applied to the central post increases until the applanation area of the cornea becomes equal to the area of the contact surface of the central post, and applanation further increases the applanation area. When the area of the contact surface is exceeded, the cornea comes into contact with the surrounding base, the force due to the rigidity of the cornea is distributed to the base, the force applied to the central post decreases, and the waveform indicating the relationship between the applanation amount and the force is downward The peak can be made. In this tonometer, at the descent point at the top of the peak, the force due to the rigidity of the cornea is regarded as being completely dispersed in the base, and the value of this descent point is adopted as the intraocular pressure.
[0005]
On the other hand, the non-contact tonometer ejects air toward the cornea and optically detects the deformed state of the cornea due to wind pressure, or when the cornea becomes flat or when the cornea becomes flat It is an apparatus which calculates | requires intraocular pressure from the internal pressure of the air ejection system.
[0006]
However, since these contact / non-contact tonometers directly apply stress to the cornea, there is a problem of giving fear to the subject.
In order to solve such a problem, in recent years, the eye to be examined is indirectly pressurized from above the eyelid with a pressurizing body, and the eye is examined based on the relative change between the amount of pressing of the pressurizing body and the load applied to the pressurizing body. A load detection type tonometer for obtaining pressure has been proposed (Japanese Patent Laid-Open Nos. 6-038930 and 6-105811).
[0007]
[Problems to be solved by the invention]
In such a load detection type tonometer, the pressing amount of the pressurizing body is obtained from the moving amount, so that in addition to the measurement of the load acting on the pressurizing body, there is a trouble of measuring the moving amount, and the measuring of the moving amount is performed. Therefore, it is necessary to position the pressurizing body with respect to the eye to be examined, which is complicated and complicated.
Further, the non-contact tonometer requires a precise optical system for determining the applanation state of the cornea, so that the apparatus is complicated and expensive.
[0008]
On the other hand, in the measurement of intraocular pressure using a contact applanation tonometer, the cornea is directly applanated, so that the subject is afraid and, as described above, eye drop anesthesia is required, and the measurement is complicated. In addition, the cornea may be damaged if the user is not familiar with the measurement operation.
In particular, in the tonometer of Japanese Patent Publication No. 8-000107 using the measurement principle of the McKay-Marg tonometer, the intraocular pressure is obtained from the value of the descent point in the waveform of the force acting on the central post. There is a problem that the processing and processing means for detection are complicated.
In addition, at this lowering point, although it is said that there is no influence of the force due to the rigidity of the cornea, the value of the lowering point is a value measured by applanating the eyeball from above the cornea, so the force due to the rigidity of the cornea Cannot be completely removed.
[0009]
  BookinventionEyesThe purpose is to provide a tonometer capable of measuring tonometry with high accuracy and low cost with a simple configuration.
[0010]
[Means for Solving the Problems]
  The present invention is a tonometer for measuring intraocular pressure of a subject's eye, a rod for applanating the subject's eye with a contact surface at a distal end, and a substantially same plane as the contact surface provided around the rod. A guide having a guide surface therein, contact force detecting means for detecting contact force when the rod and the eye to be in contact with each other, and maximum contact for obtaining a maximum value of the contact force from the detected value of the contact force The force detection means corrects the maximum value of the contact force based on an unnecessary force component included in the detection value of the contact force other than the force due to the intraocular pressure including the reaction force due to the rigidity of the cornea. A maximum value correcting means for obtaining an intraocular pressure of the optometry, and the unnecessary force component includes a standard intraocular pressure of the eye to be measured previously measured by a tonometer serving as a reference, and a maximum value of the contact force detected in advance. It is obtained based on the relationship.
  The present inventionIntraocular pressure measurement method for measuring intraocular pressure of an eye to be examinedIf explained asUsing a rod having a contact surface at the tip, the test eye is previously applanated over the entire contact surface of the rod, and the area of the contact surface and the applanation area of the test eye are the same. Measure the contact force acting on the rod,An unnecessary force component included in the detection value of the contact force is included in advance except for the force due to intraocular pressure including the reaction force due to the rigidity of the corneaIn the measurement of intraocular pressure, the eye is applanated over the entire contact surface of the rod, and the rod is in a state where the area of the contact surface and the applanation area of the eye to be examined are the same. The contact force applied to the surface was measured, and the measured value of this contact force was obtained in advance.The unnecessary force componentThe intraocular pressure of the eye to be examined is obtained by correcting based on the above.
[0011]
  Here, the contact force refers to a force per unit area applied to the contact surface of the rod when the rod and the eye to be examined come into contact with each other.
  When the spherical test eye is applanated by the rod, a contact force is applied to the rod by the repulsive force of the test eye against the applanation. This contact force includes unnecessary force components including a reaction force due to the rigidity of the cornea, in addition to a force due to intraocular pressure.
  Since this unnecessary force component is constant for each eye to be examined, the contact force when the applanation is performed on the entire contact surface of the rod (hereinafter referred to as the entire contact force) and the reference eye for a given eye to be examined The relationship with the standard intraocular pressure measured with the pressure gauge, that is, an unnecessary force component included in the contact force can be obtained.
In the present invention, the contact force applied to the rod is detected by the contact force detecting means while applanating the spherical eye to be examined with the rod and the guide. Then, due to the repulsive force against the applanation of the eye to be examined, the contact force applied to the rod increases as the eye to be examined is applanated, and when the applanation area of the eye to be examined becomes equal to the area of the contact surface of the rod. Become the maximum. In this state, the contact force includes unnecessary force components such as a force due to the rigidity of the cornea and the eyelid in addition to the force due to the intraocular pressure.
As the applanation further proceeds, the area of the applanation exceeds the area of the contact surface, the eye to be inspected contacts the guide surface around the contact surface, and the force due to the rigidity of the cornea acting on the rod is dispersed in the guide The contact force is reduced.
Thus, the contact force becomes maximum when the applanation area of the eye to be examined and the area of the contact surface are equal.
[0012]
  In the present invention, since the intraocular pressure is obtained by correcting the measured value of the entire contact force based on such a relationship, unnecessary force components including the corneal reaction force can be completely removed from the entire contact force value. Therefore, excellent measurement accuracy can be obtained.
  In addition, since the intraocular pressure can be obtained only from the contact force applied to the rod, it is not necessary to measure the amount of movement of the rod or to position it.Structure related toCan be simplified.
Since the tonometer of the present invention includes the maximum contact force detecting means for obtaining the maximum value of the contact force, the maximum value of the contact force, that is, the entire contact force can be detected easily and reliably. Therefore, as described above, if the relationship between the entire contact force and the intraocular pressure is obtained in advance, and the maximum value of the contact force is corrected based on this relationship, unnecessary force components such as the force due to the rigidity of the cornea from the entire contact force. Can be completely removed, so that highly accurate intraocular pressure measurement can be realized.
Moreover, since the maximum value can be detected by a simpler process than the detection of the descent point, the tonometer can be prevented from becoming complicated.
Furthermore, the entire contact force can be detected as the maximum contact force without observing the applanation state of the subject's eye, eliminating the need for a complex optical system like a conventional non-contact tonometer and simplifying the structure. Can be manufactured at low cost.
[0014]
Here, the maximum value of the contact force is an initial peak value (maximum value) in a waveform indicating a change in contact force due to applanation.
Further, “substantially the same plane” means that a slight error occurs with respect to the contact surface and the guide surface during the manufacture of the rod and the guide, for example, during processing or assembly.
When the spherical test eye is applanated by the rod and the guide, the contact force applied to the rod increases and becomes maximum when the applanation area of the test eye becomes equal to the area of the contact surface. As the applanation further proceeds, the area of the applanation exceeds the area of the contact surface, the eye to be inspected contacts the guide surface around the contact surface, and the force due to the rigidity of the cornea acting on the rod is dispersed in the guide The contact force is reduced.
Therefore, the maximum value of the contact force is approximately the same as the contact force when the contact surface area and the applanation area are the same, that is, the entire contact force value. Thus, even if the applanation area is not measured, it is possible to easily detect the value of the entire contact force necessary for measuring the intraocular pressure.
[0015]
And it is preferable that the said rod and a guide applanate the said to-be-tested eye from on a eyelid.
  Thus, even if the eye to be examined is applanated from above the eyelid, the force due to the rigidity of the eyelid is included in the unnecessary force component in the contact force together with the force due to the rigidity of the cornea, and thus can be removed by the correction described above. Therefore, the intraocular pressure can be measured with high accuracy.
  In addition, if this is done, the subject will not be terrified, the cornea can be prevented from being damaged, and eye drop anesthesia is no longer required, thus facilitating measurement. Therefore, since the intraocular pressure can be measured even by the examinee himself or an examiner who is not familiar with the measurement, a simple intraocular pressure measurement at home can be realized.
[0016]
In addition, as described above, in the measurement of intraocular pressure using a conventional contact applanation / non-contact tonometer, stress is directly applied to the cornea, which gives a sense of fear, and particularly when a contact applanation tonometer is used. Therefore, it is not suitable for simple intraocular pressure measurement at home because it requires skill and anesthesia.
In the present invention, since the applanation of the eye to be examined is performed from above the eyelid, fear of fear is not given to the subject, damage to the cornea can be prevented, and eye drop anesthesia is unnecessary, so that measurement can be facilitated. Therefore, it becomes possible to measure the intraocular pressure even by the subject himself / herself or an examiner who is not familiar with the measurement, and a simple intraocular pressure measurement at home can be realized.
[0022]
The tonometer is preferably provided with a fixation lamp for fixing the front of the eye that is not the subject's eye in order to fix the viewpoint of the subject's eye.
If such a fixation lamp is lit when measuring intraocular pressure and the front of the eye that is not the subject's eye is fixed, the viewpoint of the subject's eye is fixed together with the other eye so that the subject's eye can be easily Can be directly opposed.
In particular, when the subject's eye is applanated from above the eyelid, since it is difficult to make the subject's eye and the rod face each other, the effect of fixing the viewpoint with a fixation lamp is remarkably obtained.
[0023]
  Furthermore, the contact force detecting means is preferably configured to have a load cell. According to this, since the contact force can be easily configured and the contact force can be electrically detected, the contact force of the maximum contact force detecting means can be detected. The maximum value can be easily detected.
In the tonometer of the present invention, the calibration mode for obtaining the unnecessary force component and storing it in a memory, and the measurement mode for obtaining the intraocular pressure of the eye to be examined based on the unnecessary force component stored in the memory, It is preferable to have.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a tonometer 1 of the present embodiment. The tonometer 1 includes a measuring unit 10 for applanating the subject eye 4 (see FIG. 2) and detecting the reaction force, a processing unit 20 for obtaining intraocular pressure from the output of the measuring unit 10, and the subject eye 4 And a fixation lamp 30 for fixing the viewpoint.
[0025]
The measuring unit 10 includes a rod 11 for applanating the eye 4 to be examined, a guide 12 provided around the rod 11, and a load cell that is a contact force detecting unit for detecting a force applied to the rod 11. 13.
The rod 11 has a flat contact surface 11A at the tip and is formed in a cylindrical shape. The contact surface 11A presses the eye 4 to be examined from above the eyelid 41 (see FIG. 2).
The load cell 13 is connected to the base end of the rod 11 so that the force applied to the contact surface 11A can be detected by the applanation of the eye 4 to be examined. Although the type of the load cell 13 is not particularly limited, a strain gauge type load cell can be employed because the force due to intraocular pressure is relatively small.
[0026]
The guide 12 is provided in a cylindrical shape around the rod 11 and is integrally formed with a cover 14 that covers the rod 11 and the load cell 13.
An end surface of the guide 12 on the contact surface 11A side is a guide surface 12A, and the guide surface 12A is formed flush with the contact surface 11A of the rod 11 in the same plane. The contact surface 11A and the guide surface 12A constitute a flat pressure surface 10A.
[0027]
The fixation lamp 30 is arranged behind the measurement unit 10 when viewed from the eye 4 to be examined.
When measuring the intraocular pressure, the fixation lamp 30 is viewed with the other eye 5 (see FIG. 2) that is not the subject eye 4, and the position of the cornea 42 (see FIG. 2) of the subject eye 4 is fixed forward, In this state, the measuring unit 10 is moved toward the eye 4 to be examined, and the applanation surface 10A is pressed onto the cornea 42 from above the eyelid 41 to gradually applanate. Then, the force applied to the rod 11 by applanation is detected by the load cell 13.
[0028]
  The processing unit 20 includes a contact force measurement circuit 21 serving as a contact force detection unit connected to the load cell 13, a maximum value detection circuit 22 serving as a maximum contact force detection unit connected to the contact force measurement circuit 21, and the maximum Connected to the value detection circuit 22As a maximum value correction meansContact force-intraocular pressure conversion / display circuit 23, display unit 24 and memory 25 connected to this contact force-intraocular pressure conversion / display circuit 23, input means 26 and calibration arithmetic circuit 27 connected to memory 25 And is configured.
[0029]
The contact force measurement circuit 21 performs processing such as amplification of the output signal of the load cell 13 and also applies data acting as force applied to the rod 11 detected by the load cell 13 per unit area of the contact surface 11A of the rod 11. That is, the process of converting into contact force is performed.
The maximum value detection circuit 22 detects the maximum value of the contact force applied to the rod 11 from the output of the contact force measurement circuit 21.
The contact force-intraocular pressure conversion / display circuit 23 performs an after-mentioned calculation process for obtaining an intraocular pressure value from the output signal of the maximum value detection circuit 22 and causes the display unit 24 to display it.
[0030]
The memory 25 is for storing data necessary for this calculation process, for example, data of unnecessary force components (described later) included in the maximum value of the contact force.
The calibration arithmetic circuit 27 is a part for obtaining this unnecessary force component, and data necessary for the arithmetic processing here can be written into the memory 25 by the input means 26.
[0031]
The tonometer 1 of the present embodiment includes a mode selection switch (not shown), and a calibration mode for performing processing for obtaining an unnecessary force component from the maximum value of the contact force by switching the mode selection switch, and a memory 25. A measurement mode for obtaining an intraocular pressure value by performing processing based on data of an unnecessary force component in the stored contact force can be selected.
[0032]
Such intraocular pressure measurement using the tonometer 1 of the present embodiment is performed in the following procedure.
First, the tonometer 1 is set to the measurement mode by the mode selection switch, and as shown in FIG. 2, the eye 4 and the pressure plane 10A of the measuring unit 10 are opposed to each other, and the eye 4 is closed and is not the eye 4 to be examined. The other eye 5 is in an open state.
Then, the position of the cornea 42 of the eye 4 to be examined is fixed forward by viewing the fixed fixation lamp 30 with the other eye 5, and the cornea 42 is opposed to the same plane as the pressure plane 10A. .
[0033]
In this state, the measuring unit 10 is advanced toward the eye 4 to be examined, and the eyeball is applanated from above the eyelid 41. Then, the force applied to the rod 11 by applanation is detected by the load cell 13 and input to the contact force measurement circuit 21. The contact force measurement circuit 21 processes the output signal of the load cell 13 to obtain a force per unit area acting on the contact surface 11A of the rod 11, that is, a contact force.
[0034]
Here, the change of the contact force accompanying the applanation will be described with reference to FIGS.
When the applanation of the eye 4 to be examined is started from above the eyelid 41, the surface of the eyelid 41, which is the surface of the eye 4 to be examined, is a hemispherical curved surface, and as shown in FIG. The contact starts from the contact surface 11A of the pressure surface 10A ((1) in FIG. 4).
As the eye 4 is gradually applanated, the contact force gradually increases due to the repulsive force against the applanation. At this time, the applanation area S of the eye 4 to be examined is smaller than the area R of the contact surface 11A (S <R).
[0035]
If the applanation continues further, as shown in FIG. 3B, the entire contact surface 11A of the rod 11 comes into contact with the eye 4 to be examined, and the applanation area S is equal to the area R of the contact surface 11A of the rod 11. (S = R), and the contact force applied to the rod 11 is maximized at this point ((2) in FIG. 4).
Thus, in the state where only the rod 11 is in contact with the eye 4 to be examined, the reaction force of the eyelid 41 against the applanation and the reaction force of the cornea 42 act on the rod 11 together with the force due to the intraocular pressure. For this reason, in addition to the force due to intraocular pressure, the force due to the rigidity of the heel 41 and the cornea 42 is included as an unnecessary force component.
[0036]
When applanation continues, as shown in FIG. 3C, the applanation area S exceeds the area R of the contact surface 11A (S> R), and the eye 4 to be examined is a guide surface around the contact surface 11A. 12A is contacted. Then, the force due to the rigidity of the flange 41 and the force due to the rigidity of the cornea 42 that have been acting on the rod 11 so far are dispersed in the guide 12, and the contact force is reduced ((3) in FIG. 4).
Thus, the contact force applied to the rod 11 becomes maximum when the applanation area S of the eye 4 to be examined and the area R of the contact surface 11A of the rod 11 become equal.
[0037]
Such contact force data, that is, the output signal of the contact force measurement circuit 21 is input to the maximum value detection circuit 22.
The maximum value detection circuit 22 detects the first peak value from the output signal of the contact force measurement circuit 21, and the maximum value of the contact force indicated by (2) in FIG. 4, that is, the applanation area S is the contact surface 11A. The entire surface contact force, which is the contact force in a state equal to the area R of (S = R), is detected and output.
[0038]
The output signal of the maximum value detection circuit 22 is corrected by the contact force-intraocular pressure conversion / display circuit 23 based on unnecessary force component data included in the entire contact force stored in the memory 25 to obtain intraocular pressure. Detected.
That is, in the tonometer 1 of the present embodiment, the eye 4 to be examined is applanated from above the eyelid 41, so that the maximum value of the contact force includes not only the force due to the intraocular pressure but also the force due to the rigidity of the eyelid 41 and the cornea 42. The force due to the rigidity of the material is included as an unnecessary force component. Since this unnecessary force component is constant for each eye 4 to be examined, it is obtained in advance and stored in the memory 25.
[0039]
An operation for obtaining an unnecessary force component included in the entire contact force is performed before the intraocular pressure measurement.
That is, the intraocular pressure of the subject eye 4 is measured in advance using a tonometer serving as a reference, such as a Goldman tonometer, to obtain a standard intraocular pressure, and this standard intraocular pressure is input to the memory 25 by the input means 26. deep.
Then, using the tonometer 1 of this embodiment, the eye 4 to be measured is measured in the same manner as described above except that the processing mode is changed to the calibration mode by the mode selection switch. The measurement by the tonometer 1 is performed when the intraocular pressure of the eye 4 to be examined is the same as that for measuring the standard intraocular pressure, for example, immediately after the measurement of the standard intraocular pressure. As a result, the maximum value of the contact force detected by the maximum value detection circuit 22 is obtained by adding unnecessary force components such as the force due to the rigidity of the eyelid 41 and the cornea 42 to the standard intraocular pressure measured previously. .
[0040]
In the calibration mode, the output of the maximum value detection circuit 22 is input to the calibration arithmetic circuit 27. The calibration arithmetic circuit 27 reads standard intraocular pressure data measured in advance from the memory 25, compares it with the data of the maximum value of the contact force, obtains an unnecessary force component included in the maximum value, and stores it in the memory 25. Let
[0041]
The unnecessary force component data thus obtained is used for processing by the contact force-intraocular pressure conversion / display circuit 23 in the intraocular pressure measurement in the measurement mode. This contact force-intraocular pressure conversion / display circuit 23 reads out unnecessary force component data from the memory 25, removes the unnecessary force component from the maximum value of the contact force, obtains an intraocular pressure value, and the intraocular pressure value. Is displayed on the display unit 24.
[0042]
According to this embodiment, there are the following effects.
That is, the intraocular pressure of the subject eye 4 is measured in advance with a tonometer serving as a reference, and the relationship between the standard intraocular pressure and the entire contact force is obtained. Since the intraocular pressure is obtained by correcting the force value, unnecessary force components such as the force due to the rigidity of the eyelid 41 and the cornea 42 included in the entire contact force can be completely removed, so that excellent measurement accuracy can be obtained.
In addition, since the intraocular pressure can be obtained only from the contact force applied to the rod 11, it is not necessary to measure the movement amount of the rod 11 or to position it, so that the intraocular pressure measurement can be simplified.
[0043]
Further, a guide 12 having a guide surface 12A in the same plane as the contact surface 11A is provided around the rod 11, and the contact force of the rod 11 is measured while applanating the eye 4 to be examined. Therefore, even if the applanation area S is not measured, the value of the entire contact force necessary for obtaining the intraocular pressure, that is, the applanation area S and the area R of the contact surface 11A is obtained. Can easily detect the contact force at the same time.
[0044]
In addition, since the tonometer 1 of the present embodiment has the maximum value detection circuit 22, the maximum contact force value, that is, the contact force when the applanation area S and the area R of the contact surface 11A are equal (entire surface) Contact force) can be detected easily and reliably.
In addition, since the maximum value can be detected more easily than the detection of the descent point, the maximum value detection circuit 22 can be easily configured, so that the tonometer 1 can be prevented from becoming complicated.
Furthermore, since it is not necessary to determine the applanation state of the eye 4 during measurement, a complicated optical system such as a conventional non-contact tonometer is not required, and the structure can be simplified and manufactured at low cost.
Since the intraocular pressure can be obtained only from the contact force applied to the rod 11, there is no need for means for measuring the amount of movement of the rod 11 or positioning the rod 11 as in the conventional load detection tonometer. Simplification can be achieved.
[0045]
Further, by performing applanation of the eye 4 from above the eyelid 41, it is possible to prevent the subject from being afraid and to prevent the cornea 42 from being damaged and to eliminate the need for eye anesthesia, thereby facilitating measurement. it can. Therefore, it becomes possible to measure the intraocular pressure even by the subject himself / herself or an examiner who is not familiar with the measurement, and a simple intraocular pressure measurement at home can be realized.
In this case, the force due to the rigidity of the heel 41 is included in the contact force as an unnecessary force component other than the force due to the intraocular pressure together with the force due to the rigidity of the cornea 42. Since it can be removed, the intraocular pressure can be accurately measured.
[0046]
Since the tonometer 1 is provided with the fixation lamp 30, the viewpoint of the eye 4 to be examined can be fixed, so that the cornea 42 under the eyelid 41 can be easily opposed to the rod 11. it can.
[0047]
Furthermore, since the contact force is detected using the load cell 13, the configuration can be simplified and the contact force can be detected electrically, so that the maximum value can be easily detected by the maximum value detection circuit 22.
[0048]
In addition, this invention is not limited to the said embodiment, Other modifications etc. which can achieve the objective of this invention are included, The deformation | transformation etc. which are shown below are also contained in this invention.
That is, in the above embodiment, the case where the eye 4 is applanated from above the eyelid 41 has been described, but the cornea may be directly applanated with a rod. In this case, the force due to the rigidity of the eyelid is removed from unnecessary force components included in the contact force, but the intraocular pressure can be measured by the same principle as when measured from above the eyelid.
[0049]
  In the above embodiment, the force applied to the rod 11 detected by the load cell 13 is converted into the contact force by the contact force measurement circuit 21, and then the maximum value of the contact force is detected by the maximum value detection circuit 22. Before converting the force applied to the load cell into contact force data, the maximum value of the force acting on the load cell may be detected, and only this maximum value may be converted into contact force data..
  In short, the processing unit includes contact force detection means and maximum contact force detection means.Maximum value correction meansIf it contains, the structure is arbitrary.
[0050]
【The invention's effect】
  As mentioned above, the present inventionTonometerAccording to the above, the relationship between the intraocular pressure measured with the reference tonometer and the contact force when the eye to be examined is applanated over the entire contact surface of the rod is obtained in advance, and based on this relationship, the contact surface of the rod Since the intraocular pressure is obtained by correcting the measured value of the contact force when the eye is applanated over the entire surface, unnecessary force components including the reaction force of the cornea can be completely removed from the value of the entire contact force. Excellent measurement accuracy can be obtained.
  In addition, since the intraocular pressure can be obtained only from the contact force, it is not necessary to measure the amount of movement of the rod or to position it, so that the intraocular pressure measurement can be simplified.
[0051]
Further, according to the tonometer of the present invention, since the maximum contact force detecting means for obtaining the maximum value of the contact force when the eye to be examined and the rod are in contact is provided, the maximum value of the contact force, that is, the contact surface of the rod The contact force when the subject's eye is applanated over the entire surface can be detected easily and reliably.
Since the maximum value can be detected by simpler processing than the detection of the descent point, the tonometer can be prevented from becoming complicated.
Furthermore, since a means for observing the applanation state of the eye to be examined is not required, a complicated optical system such as a conventional non-contact tonometer is not necessary, and the structure can be simplified and manufactured at low cost.
Since the intraocular pressure can be obtained only from the contact force applied to the rod, there is no need for a means for measuring the amount of movement of the rod, positioning it, etc. unlike the conventional load detection type tonometer. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing a state at the time of intraocular pressure measurement using the tonometer of the embodiment.
FIG. 3 is a diagram showing an applanation state of an eye to be examined in the intraocular pressure measurement of the embodiment.
4 is a diagram showing the relationship between the contact force and the applanation amount of the eye to be examined in the embodiment. FIG.
[Explanation of symbols]
1 Tonometer
4 Eyes to be examined
11 Rod
11A Contact surface
12 Guide
12A Guide surface
13 Load cell (contact force detection means)
21 Contact force measurement circuit (contact force detection means)
22 Maximum value detection circuit (Maximum contact force detection means)
30 fixation lamp

Claims (5)

A tonometer for measuring intraocular pressure of a subject eye,
A rod for applanating the eye to be examined at the contact surface of the tip;
A guide provided around the rod and having a guide surface in substantially the same plane as the contact surface;
Contact force detection means for detecting contact force when the rod and the eye to be inspected contact each other;
Maximum contact force detection means for obtaining the maximum value of the contact force from the detected value of the contact force ;
The intraocular pressure of the eye to be examined is corrected by correcting the maximum value of the contact force based on an unnecessary force component included in the detection value of the contact force other than the force due to the intraocular pressure including the reaction force due to the rigidity of the cornea. Maximum value correction means to be obtained,
The unnecessary force component is obtained based on a relationship between a standard intraocular pressure of the eye to be examined that is measured in advance with a reference tonometer and a maximum value of the contact force detected in advance. . The tonometer according to claim 1,
The tonometer, wherein the rod and the guide applanate the eye to be examined from above the eyelid. In the tonometer according to claim 1 or 2,
A tonometer for fixing a viewpoint of the eye to be examined is provided with a fixation lamp for fixing the front of the eye that is not the eye to be examined. In the tonometer according to any one of claims 1 to 3,
The tonometer is characterized in that the contact force detecting means has a load cell.   In the tonometer according to any one of claims 1 to 4,
  A tonometer comprising: a calibration mode for obtaining the unnecessary force component and storing it in a memory; and a measurement mode for obtaining an intraocular pressure of the eye to be examined based on the unnecessary force component stored in the memory. .

Images